Promoted trihydrocarbylphosphine modified carbonyl cobalt catalyst system

ABSTRACT

The hydrogenation of cyclic and acyclic dienes to monoenes is improved by promoting trihydrocarbylphosphine modified carbonyl cobalt catalysts with alcohols, ethers, and amides.

United States Patent 1 Fahey FGD. 20, 1973 {54] PROMOTEDTRIHYDROCARBYLPHOSPHINE MODIFIED CARBONYL COBALT CATALYST SYSTEM [75]Inventor: Darryl R. Fahey, Bartlesville, Okla.

[73 Assignee: Phillips Petroleum Company [22] Filed: Jan. 8, 1971 [21]Appl. No.: 105,111

' Related US. Application Data [62] Division of Ser. No. 28,072, April13, 1970,

[52] U.S. Cl ..252/431 P, 252/431 C, 252/431 N,

260/677 H [51] Int. Cl. ..C07c 5/14, C070 5/16 [58] Field of Search..252/431 P, 431 C, 431 N [56] References Cited UNITED STATES PATENTS3,418,351 12/1968 Greene et al ..252/43l P X 3,130,237 4/1964 Wald..252/431 P X Primary ExaminerPatrick P. Garvin Attorney-Young and Quigg[57] ABSTRACT The hydrogenation of cyclic and acyclic dienes to monoenesis improved by promoting trihydrocarbylphosphinc modified carbonylcobalt catalysts with alcohols, ethers, and amides.

10 Claims, No Drawings PROMOTED TRIIIYDROCARBYLPIIOSPIIINE MODIFIEDCARBONYL COBALT CATALYST SYSTEM This application is a division of UnitedStates applicationSer. No. 28,072, filed Apr. 13, 1970, now U.S. Pat.No. 3,592,862, issued July13, 1971.

This invention relates to methods to promote the selective hydrogenationof dienes to monoenes. The invention further relates to methods toimprove trihydrocarbylphosphine modified carbonyl cobalt catalysts.

Cyclic dienes are prepared primarily by condensation reactions ofaliphatic dienes, such as the condensation of butadiene tocyclooctadiene. The cyclic dienes subsequently can be hydrogenated tothe monoene, and thereafter oxidatively cleaved to form a paraffinicdicarboxylic acid, for example cyclooctene to suberic acid. Suchsaturated dicarboxylic acids are important starting materials for theproduction of fibers, molding resins, synthetic lubricants, andplasticizers.

Acyclic dienes can be selectively hydrogenated to monoenes, thenconverted to one or more of a variety of useful end products, the choicebeing somewhat conditioned by the particular olefin, e.g., to alcohols,ethers, carboxylic acids, glycols, carbonyl compounds, epoxides,peroxides, halides, nitriles, organometallics, oligomers, polymers, andthe like.

Trihydrocarbylphosphine modified carbonyl cobalt catalysts are known tocatalyze hydrogenation reactions. However, the use of such catalysts hasnot been commercially feasible due to poor yields, rapid catalystdecomposition, or because of undesirable side reactions.

1 have discovered that trihydrocarbylphosphine modified carbonyl cobaltcatalysts can be effectively promoted and so rendered highly effectiveand useful. The promoters I use are alcohols, ethers, and amides. Mydiscovery results in promoted catalysts effective in general inproducing high yields of the monoene, with minimal side reactions, inrelatively short reaction times.

It is an object of my invention to provide an improved process for theselective hydrogenation of cyclic and acyclic dienes to thecorresponding cyclic and acyclic monoenes.

It is a further object of my invention to provide improved promotedcatalysts for these selective hydrogenation processes.

The process with which I am concerned utilizes any cyclic diolefin whichis either a conjugated diolefin, or is capable of rearranging to aconjugated structure. The nonconjugated cyclic diolefins are suitable,since I have found that they tend to rearrange progressively to aconjugated structure in the process of my reaction and with my promotedcatalysts. For example, 1,5-cyclooctadiene rearranges progressivelythrough 1,4-cyclooctadiene to 1,3-cyclooctadiene. These cyclic dienesinclude such as cyclopentadiene, cyclohexadiene, cyclododecadiene,cyclopentadecadiene, and the like, of up to carbon atoms in the cyclicstructure.

My promoted catalysts are effective, as well, in the process ofhydrogenation of acyclic diolefins having up to 20 carbon atoms in thechain. Acyclic dienes useful in the process of my invention and with mycatalysts can include such as 1,3-heptadiene, 1,5-nonadiene, 2,6, l0,14-tetramethylhexadecadiene, and the like.

The dienes, cyclic and acyclic, can be substituted with any substituentthat will not interreact with the catalysts, the reaction diluent, theparaffinic diluent for the promoter, or the products of reaction.Substituents can include alkyl or aryl groups.

The catalysts which I use in my reactions, and which I promote accordingto the process of my reaction, are trihydrocarbylphosphine carbonylcobalt catalysts:

Within the above trihydrocarbylphosphine modified carbonyl cobaltcatalysts, R can be alkyl of up to six carbon atoms such as methyl,ethyl, propyl, butyl, and the like, or cycloalkyl such as cyclohexyl offrom five to seven carbon atoms, or can be aryl such as phenyl orsubstituted aryl containing up to three substituents of up to threecarbon atoms per substituent. A presently preferred catalyst istricarbonylbis( tributylphosphine )c obalt(l)tetracarbonylcobaltate(-l). A synthesis of the preferred catalyst isshown in one of the examples given hereinafter.

The amount of catalyst employed, the trihydrocarbylphosphine modifiedcarbonyl cobalt, usually is based on the amount of diene to behydrogenated. A weight ratio of catalyst to diene of 0.008 to 1,preferably 0.025 to 0.08, is useful. There actually appears noparticular upper limit in the amount of catalyst used except on a basisof cost.

The promoters that I use are selected from alcohols, ethers, and amides.The useful alcohols within the context of my promoters are thosecontaining from one to eight carbon atoms, are saturated, and preferablyprimary. The ethers which are useful in the context of my promoters arethe dialkyl ethers wherein the alkyl group corresponds to thosedescribed for the alcohols above. Combination alcohol-ethers also areguide suitable within my invention, such as 2-methoxyethanol.

Amides, more particularly N,N-disubstituted aliphatic amides are usefulpromoters for these catalysts and reactions. The substituents on thenitrogen can be any alkyl group ranging from one to eight carbon atomsper substituent. The amide itself can be formamide, acetamide, or otheraliphatic amide grouping, including branched as well as straight-chain,of up to eight carbon atoms. A promoter to catalyst weight ratio is usedbroadly of from 0.06 to 40, preferably of from 0.6 to 20.

The following examples illustrate the effectiveness and the versatilityof the promotors of my invention. The examples should not be consideredlimitative of either the promoters or the process of my invention.

EXAMPLE I In preparation of the catalyst, 3.42 g (gram) (0.01 mole) ofdicobalt octacarbonyl, 50 ml (milliliters) of anhydrous diethyl ether,and 4.04 g (0.02 mole) of tributyl phosphine, were charged in that orderto a 7 ounce reactor with air excluded. The mixture was stirred,normally 1 to 2 hours being sufficient, at a few millimeters pressurereduction less than atmospheric in order to avoid carbon monoxidebuildup. The crystalline product which formed was collected, washed withdiethyl ether, and dried on a sintered glass filter with a minimum ofatmospheric exposure. The yield of catalyst obtained was 6.57 g orapproximately 91.6 percent of theoretical. The catalyst obtained wastricarbonylbis(tributylphosphine)cobalt(l) tetracarbonylcobaltate(-I)with a melting point of 114 to 115 C., showing high purity.

In a selective hydrogenation reaction employing my 1 catalyst, a 3 ounceaerosol compatibility tube containing a Teflon covered magnetic stirringbar was charged with 0.12 g (0.17 mmole) of the trihydrocarbylphosphinemodified carbonyl cobalt catalyst. described above together with 2.11 g(18.6 mmole) of 1,5- cyclooctadiene, 2.0 ml of l-butanol, and 30 m1 ofcyclohexane. For the control run the same ingredients and samecomponents were used except omitting the 1 -butanol promoter. Afteradding the ingredients, the reaction tube was sealed quickly, degassedunder vacuum, and pressurized to approximately 180 psig using hydrogen.The tube was immersed in an oil bath, and the temperature of the bathwas increased to the range of from 140 to 155 C. over approximately a150 minute interval. The reaction mixture was magnetically stirred at arapid rate at all times during the reaction period. Hydrogen adsorptionbegan at a temperature of about 135 C. Additional hydrogen wasintroduced into the reaction vessel to maintain a pressure between about200 and 210 psig. When the hydrogen uptake had ceased, the reaction wasstopped.

The crude reaction mixture was analyzed by gasliquid partitionchromatography. The results of the comparative runs with and without mypromoter are shown in the following table.

TABLE I Unreacted Cyclooctene Cyclooctane Run Wt.% Wt.% Wt.%

l Control 45.6 50.5 3.9 2 With 1 -butanol 92.2 7.7

The comparative runs above show dramatically an 85 percent increase information of cyclooctene by the use of the catalysts with my promoter asopposed to no promoter, and furthermore show that essentially all of thestarting material had reacted.

EXAMPLE 11 TABLE 11 Run Promoter Product Analysis, Wt.% No. and AmountCyclo' Cyclo- Cyclooctadiene octene octane 3 Z-methoxyethanol, 1.9 g 088.7 1 1.2

4 bis( Z-methoxyethyl )ether,

1.9 g 0 91.8 8.1 5 tetrahydrofuran, 2.2 g 0 92.0 8.0 6dimethylsulfoxide, 2.2 g 86.2 13.9 0 7 N,N-dimethy1formamide,

The above results show that alcohols other than the l-butanol used inExample 1 are effective, i.e., 2- methoxyethanol in Run 3. Also thatethers as in Runs 3 and 4 are effective. The amides, such as theN,N-disubstituted amide in Run 7, are effective. The cyclic ethers, asin Run 5 also are effective. However, the disubstituted sulfoxide of Run6 is not effective as a promoter.

EXAMPLE 111 A wide range of other alcohol promoters can be used in myinvention. The following table shows the results of using variouspromoters, each an alcohol, under reaction conditions exactly asdescribed in Example 11 above.

TABLE 111 Run Product Analysis, Wt. No. Promoter Cyclo- Cyclo-Cyclooctadiene octene octane 8 Methanol 0.8 90.0 9.1 9 Ethanol 15.6 .29.2 10 l-Butanol 92.0 8.0 1 l Ethylene glycol 60.6 38.0 1.3

Run 11 using ethylene glycol demonstrates that a glycol is not useful.

EXAMPLE IV A further series of runs were made employing 0.12 g (0.17mmole) of the catalyst, 2.l1 g (0.0195 mole) of 1,5-cyclooctadiene, 30.0ml of cyclohexane diluent, otherwise following the procedure asdescribed in Example I hereinabove. In each of the runs in this example,l'butanol was used as the promoter, however, the amount of l-butanol wasvaried. The results are shown in Table IV below:

The above data indicate a l-butanol molarity of approximately 0.17 inthe diluent is optimum. However, the promotional effect of l-butanol isstrongly evident over a concentration range as broad as 0.034 to 0.62molar. Additionally, the data indicate that, in the absence of adiluent, both the conversion of cyclooctadiene and the selectivity tocyclooctene are impaired.

As I have expressed above, and particularly as shown by comparing Run 16with previous runs, a paraffinic diluent results in improved resultsover runs with the catalyst promoted with materials as I have discussed,but without diluent.

My promoters can be used in a broad concentration of between 0.0005 and5 molarity of the promoter in the diluent used. I prefer a range ofabout 0.01 to about 1 molar as giving effective results.

The diluent, where used, can include such as the paraffin hydrocarbons,both cyclic and acyclic, such as n-pentane, n-hexane, cyclooctane,isodecane, and similar diluents of up to about 12 carbon atoms permolecule. The amount of diluent is adjusted according to the amount ofdiene to be hydrogenated, and ranges from a diluent to diene ratio offrom 111,000 to 1:5, though a ratio of about 1:50 is preferred. Toolittle diluent appears to shorten catalyst life, and large quantities ofdiluent are undesirable in terms of materials handling.

Reaction conditions include the use of hydrogen, of course, togetherwith a reaction pressure in the range of from about 1 to as much as 700psig, though preferably 100 to about 250 psig. As hydrogen pressure iselevated, reaction rates increase, however the selectivity toward themonoene appears to decrease. The hydrogen used can be diluted with inertgas, such as a low molecular weight paraffin, nitrogen, or a rare gas,if desired, since dilution of the hydrogen tends to slow the reactionand thus is useful as a means of moderating rate of reaction.

Reaction temperatures can range from 125 C. to as much as 180 0, thougha moderate range of between 135 and 155 C. is more commonly employed.The catalysts are temperature sensitive and tend to decompose aboveabout 180 C. Reaction time ranges from a minute to as much as 24 hours,more usually from 1 to 3 hours. In practice, reaction conditions aremaintained until hydrogen uptake ceases or substantially ceases. Thecatalysts tend to be sensitive to both oxygen and moisture. Therefore,the selective hydrogenation preferably is carried out with the exclusionof oxygen and moisture.

In my examples and discussion I have shown the effectiveness of avariety of promoters for trihydrocarbylophosphine modified carbonylcobalt catalysts. Variations are possible within the scope of myinvention, yet without departing from the true scope and spirit thereof.

1 claim:

1. A promoted trihydrocarbylphosphine modified carbonyl cobalt catalystwherein the trihydrocarbylphosphine carbonyl cobalt is represented by[Co(CO) (PR ][Co(CO) wherein each R is alkyl of up to six carbon atoms,cycloalkyl of up to seven carbon atoms, or aryl, and said R has fromzero to three alkyl substituents of up to three carbon atoms persubstituent, and wherein the promoter of said promoted catalyst isdialkyl ether or alkoxy alkanol containing up to eight carbon atoms peralkyl group.

2. The catalyst according to claim 1 wherein the mole ratio of saidpromoter to said trihydrocarbylphosphine carbonyl cobalt is about 0.06to 40.

3. The catalyst according to claim 2 further employing a paraffinicdiluent of up to 12 carbon atoms per molecule or mixture thereof.

4. The catalyst according to claim 3 employing a molarity of saidpromoter in said paraffinic diluent of about 0.0005 to 5.

5. An essentially anhydrous promoted trihydrocarbylphosphine modifiedcarbonyl cobalt catalyst system wherein the trihydrocarbylphosphinecarbonyl cobalt portion thereof is represented by [Co(CO) (PR Co(CO),,]wherein each R is an alkyl of up to six carbon atoms, cycloalkyl of upto seven carbon atoms, or

aryl, and said R has from zero to three alkyl substituents of up tothree carbon atoms per substituent, and the promoter thereof is alkanol,dialkyl ether, dialkyl amide, or alkoxy-alkanol, and a paraffinic cyclicor acyclic diluent of up to 12 carbon atoms per molecule.

6. The catalyst system according to claim 5 wherein the mole ratio ofsaid promoter to said [Co(CO);,(PR ][Co(CO) is about 0.06 to 40, and themolarity of said promoter in said paraffinic diluent is about 0.0005 to5.

7. The catalyst system according to claim 6 wherein said promoter issaid alkanol and contains up to four carbon atoms.

8. The catalyst system according to claim 7 wherein said promoter ismethanol, ethanol or n-butanol, said )a( 3)2][ )4] is )3( 3)2][ Co(COwherein Bu is butyl, and said paraffinic diluent is cyclohexane.

9. The catalyst system according to claim 5 wherein said promoter is2-methoxyethanol, bis(Z-methoxyethyl)ether, or tetrahydrofuran, said[Co(CO) (PR ][Co(CO),] is [Co(CO) (PBu ][Co(CO) ]wherein Co(CO),,]Bu isbutyl, and said paraffinic diluent is cyclohexane.

10. A promoted trihydrocarbylphosphine modified carbonyl cobalt catalystsystem consisting essentially of:

I. [Co(CO) (PBu ][Co(CO) wherein Bu is butyl,

and

II. a promoter wherein said promoter is 2-methoxyethanol,bis(Z-methoxyethyl)ether, or tetrahydrofuran,

wherein the mole ratio of said (II):(I) is from 0.6 to

1. A promoted trihydrocarbylphosphine modified carbonyl cobalt catalystwherein the trihydrocarbylphosphine carbonyl cobalt is represented by(Co(CO)3(PR3)2)(Co(CO)4) wherein each R is alkyl of up to six carbonatoms, cycloalkyl of up to seven carbon atoms, or aryl, and said R hasfrom zero to three alkyl substituents of up to three carbon atoms persubstituent, and wherein the promoter of said promoted catalyst isdialkyl ether or alkoxy alkanol containing up to eight carbon atoms peralkyl group.
 2. The catalyst according to claim 1 wherein the mole ratioof said promoter to said trihydrocarbylphosphine carbonyl cobalt isabout 0.06 to
 40. 3. The catalyst according to claim 2 further employinga paraffinic diluent of up to 12 carbon atoms per molecule or mixturethereof.
 4. The catalyst according to claim 3 employing a molarity ofsaid promoter in said paraffinic diluent of about 0.0005 to
 5. 5. Anessentially anhydrous promoted trihydrocarbylphosphine modified carbonylcobalt catalyst system wherein the trihydrocarbylphosphine carbonylcobalt portion thereof is represented by (Co(CO)3(PR3)2)(Co(CO)4)wherein each R is an alkyl of up to six carbon atoms, cycloalkyl of upto seven carbon atoms, or aryl, and said R has from zero to three alkylsubstituents of up to three carbon atoms per substituent, and thepromoter thereof is alkanol, dialkyl ether, dialkyl amide, oralkoxy-alkanol, and a paraffinic cyclic or acyclic diluent of up to 12carbon atoms per molecule.
 6. The catalyst system according to claim 5wherein the mole ratio of said promoter to said (Co(CO)3(PR3)2)(Co(CO)4)is about 0.06 to 40, and the molarity of said promoter in saidparaffinic diluent is about 0.0005 to
 5. 7. The catalyst systemaccording to claim 6 wherein said promoter is said alkanol and containsup to four carbon atoms.
 8. The catalyst system according to claim 7wherein said promoter is methanol, ethanol or n-butanol, said(Co(CO)3(PR3)2)(CO(CO)4) is (Co(CO)3(PBu3)2)(Co(CO)4) wherein Bu isbutyl, and said paraffinic diluent is cyclohexane.
 9. The catalystsystem according to claim 5 wherein said promoter is 2-methoxyethanol,bis(2-methoxyethyl)ether, or tetrahydrofuran, said(Co(CO)3(PR3)2)(Co(CO)4) is (Co(CO)3(PBu3)2)(Co(CO)4)wherein Co(CO)4)Buis butyl, and said paraffinic diluent is cyclohexane.